1. Field of the Invention:
This invention relates to an air conditioning system and, in particular, to a system having integral energy conservation means.
2. Prior Art
Air conditioning systems for providing one or more zones of controlled air temperature within a building have commonly employed a single thermostatic device in the controlled zone of the building which is operative to activate air heating or cooling means in response to deviation of the control zone temperature below or above a single set point temperature. In some of these systems, such as that disclosed in U.S. Pat. No. 3,567,115, the proportions of fresh and return air circulated through the system are varied in response to the heat content of the outside air and the heating and cooling demands of the controlled zone or zones. Central air conditioning systems are commonly employed to supply multiple zones and, in such applications, each zone can be provided with individual zone dampers in its cold air supply duct and in its hot air supply duct. These individual dampers are actuated in response to the temperature of the respective zone and have been mechanically interconnected and actuated by a common drive in the manner described in U.S. Pat. No. 3,788,386. The control means employed in air conditioning systems supplying multiple zones commonly have selective means whereby the air heating or cooling facilities of the system are controlled by the signal from the zone having the greatest demand for heating or cooling as described in U.S. Pat. No. 3,338,519.
While some attempts have been made to improve the efficiency of air conditioning systems, such as by providing primary and secondary air heating and cooling equipment and by operating this equipment under conditions which minimize cycling of the large energy demand primary facilities, heretofore, no attempt has been made to provide an air conditioning system that would include integral energy conservation means. In particular, no prior attempt has been made to provide an air conditioning system which has a low temperature set point for control of the heating and ventilation facilities with a higher temperature set point for control of the air cooling facilities.